Tuberculosis-infected dairy herd discovered in Tulare County

A herd of cows testing positive for bovine tuberculosis has been found in a Tulare County.

The California Department of Food and Agriculture announced today that state and federal scientists had confirmed the diagnosis, and state officials are working with the dairy and a local veterinarian to prevent the spread of the disease.

A CDFA press release didn’t disclose the name of the dairy where the infected cows were found or specify what area of the count the herd is located.

The diagnosis of TB was made after a suspicious mass was detected in a cow during routine slaughter inspection. After that, CDFA veterinarians, working with their counterparts in the U.S. Department of Agriculture began testing herds that may have come in contact with the infected cow, leading to the detection of the tuberculosis-infected herd, the CDFA reports.

Officials didn’t disclose in their press release when the discoveries were made.

Tuberculosis is a chronic, slow-spreading disease that can remain undetected for years. Infected animals, even those that appear healthy, can spread infection to other animals, the CDFA reports.

Bovine tuberculosis — or “mycobacterium bovis” — can, in some cases, infect humans. But generally, most humans are at low risk for infection, even if they eat or drink contaminated or unpasteurized dairy products, according the Centers for Disease Control and Prevention.

People at greater risk are those who work with cattle, bison, deer or elk, as well as people who work with products made from these animals, including hides, milk or meat.

The CDC reports that people who drink unpasteurized — or “raw” — milk or consume dairy products made from raw milk are also at greater risk.

Almost all milk sold in California is pasteurized to destroy organisms that could be harmful to humans, including tuberculosis organisms. And milk from the state’s raw milk dairies regularly are tested for them, according to the CDFA.

In addition, the agency reports that that all cattle processed for meat is inspected for signs of tuberculosis and rejected if they show signs of the disease, which is how the infected Tulare County cows were discovered.

Last year, two Tulare County dairies were quarantined after a dead cow from one of the dairies that was sent to a rendering plant was found to be infected bovine spongiform encephalopathy — also known as “BSE” and “mad cow disease.”

It was the first BSE-infected cow discovered in California and the fourth in the United States. The neurological disease can be fatal to cows and cause variant Creutzfeldt-Jakob disease – a fatal neurodegenerative disease – in humans who eat infected brain matter or spinal tissue from the animals.